【ocean】测试phaseDeg，phaseDegUnwrapped和phaseMargin

• 对二级运放进行测试
  -101.35,78.01,78.01

   GBW = gainBwProd((VF("/Vout2") / VF("/Vin")))
   PHASE = phaseDegUnwrapped((VF("/Vout2") / VF("/Vin")))
   plot( PHASE ?expr '( "PHASE" ) ) 
   PHASEdeg = phaseDeg((VF("/Vout2") / VF("/Vin")))
   plot( PHASEdeg ?expr '( "PHASEdeg" ) )    


   phase_GBW = value(PHASE GBW)
   PHASEdeg_GBW = value(PHASEdeg, GBW)
   PHASEmargin = phaseMargin((VF("/Vout2") / VF("/Vin")))
   printf("%5.2f,%5.2f,%5.2f\n", PHASEmargin,PHASEdeg_GBW,phase_GBW )

• ocean文档里的解释，phase类似于phaseDegUnwrapped
  The phase command is similar to the phaseDegUnwrapped command and returns the
  unwrapped phase in degrees.
• phasemargin测试loop gain